Articles such as CPUs, calculators and word processors are valuable enough to be worth stealing. For this reason, security means have been provided which hold them against unauthorized removal. One well known family of security devices is exemplified by Gassaway patent Nos.3,850,392 and 3,910,079.
A characteristic of the Gassaway device, which is in widespread usage, is a rigid base plate held to a base structure such as a desk or a counter by a pad. The pad is made of a dense structural foam, and is faced on both of its sides with a pressure-sensitive adhesive. When the plate is adhered to the mat, and the mat is adhered to the base structure, the plate will be firmly held. The plate is provided with lock means removably to attach a protected article to it. The article can then be removed only by authorized manipulation of the lock means.
Various arrangements are made in Gassaway-type devices to frustrate removal of the plate from the base structure. The most obvious approach to removal is to cut the mat, or to pry the base plate off of the surface. These procedures are opposed by means which prevent entry of a garrot wire, or exertion of peeling forces on the adhesive by prying up on the base plate.
It is always possible for a thief to overcome reasonable security precautions if he is willing to risk the price of interception, or of damage to the stolen goods, which must be fenced for him to profit. With the use of sufficient tooling for cutting or prying, a thief can remove the article from its base structure. However, he must bring the tools with him and take the time necessary to use them.
Herein lies the advantage of the adhesive pad. It is very resistant to separative tensile forces, so that very strong forces must be exerted to remove it from a base structure. These forces will often damage the base plate and the goods and render them unsalable. While it is of no concern to the thief, they will usually also harm the desk or the counter--but sometimes pieces of those will come off along with the article.
Thus, the objectives of the base plate are robe rigid and to protect the pad against lateral access and peeling, while the pad must resist tensile removal (popping off). Clearly this is intended to be a strong permanent attachment. Now the problem arises: what it one wants to move the protected article to another location and to remove the base plate from the base structure? The very design of the base plate and mat are intended to frustrate this purpose.
Adhesively mounted base plates are sometimes removed by heating them to a temperature which will sufficiently soften the foam or the adhesive that the metal plate can be removed. Sometimes the plate takes all of the mat with it, and sometimes not. Sometimes the temperature attained is low enough that a desk surface will not be damaged and sometimes not. These are serious problems in an office.
These are not the concerns of a thief. Generally, if a theft can not be completed in five minutes, it should not be attempted. If it takes more than five minutes for the heat process, the heat process will not be used. For this reason, more stringent forces are most frequently used to steal the protected article.
It is an object of this invention to provide means to remove a rigid base plate and its adhesive mat from a base structure with minimal or no damage to the surface of the structure, and without applying heat. Here, advantage is taken of an inherent property of the pad and its adhesive--it is vulnerable to a gradual peeling force. A gradual peeling force is precisely what the thief can not tolerate. He does not have time for a benign process that may take a half hour or longer--he must be away in about five minutes or take the risk of interception.
Not only can the base plate be removed (along with the pad) with this invention, but in a second procedure the pad can be removed from the plate, so the more expensive plate can be reused by applying a replacement pad.